1. Field of the Invention
This invention relates to an electrical wiring distribution system including metal cellular flooring units adapted to be embedded in concrete and which present alternating troughs and enclosed cells, and more particularly to an improved metal cellular floor unit adapted to convey three different electrical services, such as, power, telephone and CRT services.
2. Description of the Prior Art
Heretofore, distribution systems have distributed the wiring of two different services, that is power and telephone. The ever-increasing use of computers and other terminal-to-terminal communications equipment, necessitates the distribution of three different services, that is power, telephone and a computer or the like services.
Flooring units for distributing the wiring of three different services throughout a building floor are known in the Prior Art. Such a flooring unit is disclosed in U.S. Pat. No. 3,459,875 (FORK) wherein three separate cells of the flooring units, each convey a different electrical service. Different arrangements of conduit means connecting adjacent cells and outlet openings provide access to all three electrical services at a single location in the flooring unit.
Another type of flooring unit is disclosed in U.S. Pat. Nos. 3,592,956 (FORK) and 4,178,469 (FORK) wherein capping means encloses the trough space between adjacent cells to provide an additional unobstructed electrical passageway. An arrangement of access openings and partitions provides access to each of the three services at a single location in the floor. Such metal cellular units provide unique solutions for the three-service distribution in reinforced concrete floor structures. However, these metal cellular units find little utility in metal sub-floor/concrete floor structures for two principal reasons. A number of the troughs are unavailable for placement of shear studs with a corresponding reduction in the composite beam strength of the floor. In addition, the capping means maintain the capped troughs in a concrete-free status. Therefore the amount of concrete which would normally be available to serve as a heat sink during a fire is significantly reduced and the fire resistance of the floor structure is likewise reduced.
Another such flooring unit is disclosed in U.S. Pat. No. 3,751,576 (KLINKMAN et al) wherein a relatively wide single cell unit is divided into three separate subcells by partitions integrally formed in the bottom sheet of the unit. A single relatively wide access opening in the crest of the unit provides access to each subcell and to the wiring conveyed therethrough. Such a unit, commonly known as a plural-cell duct, finds utility in reinforced concrete floor structures wherein the unit is not intended to serve as a structural component of the floor structure.